Random Access Resource Selection on Non-Anchor Carriers
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Solution Overview
Problem
In NB-IoT systems, user equipment (UE) faces challenges in accurately selecting resources on non-anchor carriers for random access due to the lack of narrowband reference signals, leading to a low success rate of random access operations.
Innovation Solution
The method involves measuring reference signal received power (RSRP) on an anchor carrier for an extended period, determining a coverage level based on the measurement, and using this information to select a resource on a non-anchor carrier, while adjusting transmit power to improve the signal-to-interference plus noise ratio, thereby enhancing resource selection accuracy and random access success.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE performs random access on non-anchor carrier using prior art measurement period, then random access can be initiated, but resource selection accuracy is low leading to low success rate
Solution Approach 1:
The patent performs preliminary RSRP measurements on the anchor carrier before initiating random access on the non-anchor carrier. By measuring the RSRP of the anchor carrier's reference signal in advance and determining the coverage level based on this measurement, the UE can select an appropriate random access resource on the non-anchor carrier, thereby improving resource selection accuracy and random access success rate.
2Measurement precision
If measurement period is extended to improve RSRP measurement precision, then resource selection accuracy improves, but power consumption increases
Solution Approach 1:
The patent extends the measurement period T1 for RSRP measurements on the anchor carrier beyond the prior art's 800ms duration. By increasing the measurement period to values such as 1000ms, 1200ms, 1400ms, or 1600ms, the UE achieves more precise RSRP measurements and improved coverage level determination, thereby enhancing resource selection accuracy for random access on non-anchor carriers.
3Adaptability or versatility
If UE can only perform random access on anchor carrier, then resource selection is straightforward, but communication requirements cannot be met
Solution Approach 1:
The patent uses the anchor carrier as an intermediary to enable random access on non-anchor carriers. Since the anchor carrier carries reference signals that can be measured, the UE measures the RSRP on the anchor carrier and uses this measurement to determine coverage level and select appropriate random access resources on the non-anchor carrier, which do not carry reference signals themselves.
Data Source
AI summary
Embodiments of the present invention relate to the field of communications technologies, and provide a random access method and an apparatus, to resolve a prior-art problem that user equipment cannot accurately select a resource on a non-anchor carrier to perform random access. The method includes: measuring, by user equipment UE in a first measurement period T1, reference signal received power (RSRP) W1 on an anchor carrier; determining, by the UE, a first coverage level based on W1; and determining, by the UE, a first resource based on the first coverage level, where the first resource is used by the UE to perform random access on a non-anchor carrier.